/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.mariotaku.twidere.fragment.support;

import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.ListAdapter;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.etsy.android.grid.StaggeredGridView;

import org.mariotaku.twidere.R;

/**
 * Static library support version of the framework's
 * {@link android.app.ListFragment}. Used to write apps that run on platforms
 * prior to Android 3.0. When running on Android 3.0 or above, this
 * implementation is still used; it does not try to switch to the framework's
 * implementation. See the framework SDK documentation for a class overview.
 */
public class StaggeredGridFragment extends Fragment {
	static final int INTERNAL_EMPTY_ID = 0x00ff0001;
	static final int INTERNAL_PROGRESS_CONTAINER_ID = 0x00ff0002;
	static final int INTERNAL_LIST_CONTAINER_ID = 0x00ff0003;

	final private Handler mHandler = new Handler();

	final private Runnable mRequestFocus = new Runnable() {
		@Override
		public void run() {
			mList.focusableViewAvailable(mList);
		}
	};

	final private AdapterView.OnItemClickListener mOnClickListener = new AdapterView.OnItemClickListener() {
		@Override
		public void onItemClick(final AdapterView<?> parent, final View v, final int position, final long id) {
			onListItemClick((StaggeredGridView) parent, v, position, id);
		}
	};

	ListAdapter mAdapter;
	StaggeredGridView mList;
	View mEmptyView;
	TextView mStandardEmptyView;
	View mProgressContainer;
	View mListContainer;
	CharSequence mEmptyText;
	boolean mListShown;

	public StaggeredGridFragment() {
	}

	/**
	 * Get the ListAdapter associated with this activity's ListView.
	 */
	public ListAdapter getListAdapter() {
		return mAdapter;
	}

	/**
	 * Get the activity's list view widget.
	 */
	public StaggeredGridView getListView() {
		ensureList();
		return mList;
	}

	/**
	 * Get the cursor row ID of the currently selected list item.
	 */
	public long getSelectedItemId() {
		ensureList();
		return mList.getSelectedItemId();
	}

	/**
	 * Get the position of the currently selected list item.
	 */
	public int getSelectedItemPosition() {
		ensureList();
		return mList.getSelectedItemPosition();
	}

	/**
	 * Provide default implementation to return a simple list view. Subclasses
	 * can override to replace with their own layout. If doing so, the returned
	 * view hierarchy <em>must</em> have a ListView whose id is
	 * {@link android.R.id#list android.R.id.list} and can optionally have a
	 * sibling view id {@link android.R.id#empty android.R.id.empty} that is to
	 * be shown when the list is empty.
	 * 
	 * <p>
	 * If you are overriding this method with your own custom content, consider
	 * including the standard layout {@link android.R.layout#list_content} in
	 * your layout file, so that you continue to retain all of the standard
	 * behavior of ListFragment. In particular, this is currently the only way
	 * to have the built-in indeterminant progress state be shown.
	 */
	@Override
	public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) {
		final Context context = getActivity();

		final FrameLayout root = new FrameLayout(context);

		// ------------------------------------------------------------------

		final LinearLayout pframe = new LinearLayout(context);
		pframe.setId(INTERNAL_PROGRESS_CONTAINER_ID);
		pframe.setOrientation(LinearLayout.VERTICAL);
		pframe.setVisibility(View.GONE);
		pframe.setGravity(Gravity.CENTER);

		final ProgressBar progress = new ProgressBar(context, null, android.R.attr.progressBarStyleLarge);
		pframe.addView(progress, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
				ViewGroup.LayoutParams.WRAP_CONTENT));

		root.addView(pframe, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
				ViewGroup.LayoutParams.MATCH_PARENT));

		// ------------------------------------------------------------------

		final FrameLayout lframe = new FrameLayout(context);
		lframe.setId(INTERNAL_LIST_CONTAINER_ID);

		final TextView tv = new TextView(getActivity());
		tv.setId(INTERNAL_EMPTY_ID);
		tv.setGravity(Gravity.CENTER);
		lframe.addView(tv, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
				ViewGroup.LayoutParams.MATCH_PARENT));

		final StaggeredGridView lv = (StaggeredGridView) inflater.inflate(R.layout.staggered_gridview, lframe, false);
		lv.setId(android.R.id.list);
		lv.setDrawSelectorOnTop(false);
		lframe.addView(lv, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
				ViewGroup.LayoutParams.MATCH_PARENT));

		root.addView(lframe, new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
				ViewGroup.LayoutParams.MATCH_PARENT));

		// ------------------------------------------------------------------

		root.setLayoutParams(new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
				ViewGroup.LayoutParams.MATCH_PARENT));

		return root;
	}

	/**
	 * Detach from list view.
	 */
	@Override
	public void onDestroyView() {
		mHandler.removeCallbacks(mRequestFocus);
		mList = null;
		mListShown = false;
		mEmptyView = mProgressContainer = mListContainer = null;
		mStandardEmptyView = null;
		super.onDestroyView();
	}

	/**
	 * This method will be called when an item in the list is selected.
	 * Subclasses should override. Subclasses can call
	 * getListView().getItemAtPosition(position) if they need to access the data
	 * associated with the selected item.
	 * 
	 * @param l The ListView where the click happened
	 * @param v The view that was clicked within the ListView
	 * @param position The position of the view in the list
	 * @param id The row id of the item that was clicked
	 */
	public void onListItemClick(final StaggeredGridView l, final View v, final int position, final long id) {
	}

	/**
	 * Attach to list view once the view hierarchy has been created.
	 */
	@Override
	public void onViewCreated(final View view, final Bundle savedInstanceState) {
		super.onViewCreated(view, savedInstanceState);
		ensureList();
	}

	/**
	 * The default content for a ListFragment has a TextView that can be shown
	 * when the list is empty. If you would like to have it shown, call this
	 * method to supply the text it should use.
	 */
	public void setEmptyText(final CharSequence text) {
		ensureList();
		if (mStandardEmptyView == null) throw new IllegalStateException("Can't be used with a custom content view");
		mStandardEmptyView.setText(text);
		if (mEmptyText == null) {
			mList.setEmptyView(mStandardEmptyView);
		}
		mEmptyText = text;
	}

	/**
	 * Provide the cursor for the list view.
	 */
	public void setListAdapter(final ListAdapter adapter) {
		final boolean hadAdapter = mAdapter != null;
		mAdapter = adapter;
		if (mList != null) {
			mList.setAdapter(adapter);
			if (!mListShown && !hadAdapter) {
				// The list was hidden, and previously didn't have an
				// adapter. It is now time to show it.
				setListShown(true, getView().getWindowToken() != null);
			}
		}
	}

	/**
	 * Control whether the list is being displayed. You can make it not
	 * displayed if you are waiting for the initial data to show in it. During
	 * this time an indeterminant progress indicator will be shown instead.
	 * 
	 * <p>
	 * Applications do not normally need to use this themselves. The default
	 * behavior of ListFragment is to start with the list not being shown, only
	 * showing it once an adapter is given with
	 * {@link #setListAdapter(ListAdapter)}. If the list at that point had not
	 * been shown, when it does get shown it will be do without the user ever
	 * seeing the hidden state.
	 * 
	 * @param shown If true, the list view is shown; if false, the progress
	 *            indicator. The initial value is true.
	 */
	public void setListShown(final boolean shown) {
		setListShown(shown, true);
	}

	/**
	 * Like {@link #setListShown(boolean)}, but no animation is used when
	 * transitioning from the previous state.
	 */
	public void setListShownNoAnimation(final boolean shown) {
		setListShown(shown, false);
	}

	/**
	 * Set the currently selected list item to the specified position with the
	 * adapter's data
	 * 
	 * @param position
	 */
	public void setSelection(final int position) {
		ensureList();
		mList.setSelection(position);
	}

	private void ensureList() {
		if (mList != null) return;
		final View root = getView();
		if (root == null) throw new IllegalStateException("Content view not yet created");
		if (root instanceof StaggeredGridView) {
			mList = (StaggeredGridView) root;
		} else {
			mStandardEmptyView = (TextView) root.findViewById(INTERNAL_EMPTY_ID);
			if (mStandardEmptyView == null) {
				mEmptyView = root.findViewById(android.R.id.empty);
			} else {
				mStandardEmptyView.setVisibility(View.GONE);
			}
			mProgressContainer = root.findViewById(INTERNAL_PROGRESS_CONTAINER_ID);
			mListContainer = root.findViewById(INTERNAL_LIST_CONTAINER_ID);
			final View rawListView = root.findViewById(android.R.id.list);
			if (!(rawListView instanceof StaggeredGridView)) {
				if (rawListView == null)
					throw new RuntimeException("Your content must have a StaggeredGridView whose id attribute is "
							+ "'android.R.id.list'");
				throw new RuntimeException("Content has view with id attribute 'android.R.id.list' "
						+ "that is not a StaggeredGridView class");
			}
			mList = (StaggeredGridView) rawListView;
			if (mEmptyView != null) {
				mList.setEmptyView(mEmptyView);
			} else if (mEmptyText != null) {
				mStandardEmptyView.setText(mEmptyText);
				mList.setEmptyView(mStandardEmptyView);
			}
		}
		mListShown = true;
		mList.setOnItemClickListener(mOnClickListener);
		if (mAdapter != null) {
			final ListAdapter adapter = mAdapter;
			mAdapter = null;
			setListAdapter(adapter);
		} else {
			// We are starting without an adapter, so assume we won't
			// have our data right away and start with the progress indicator.
			if (mProgressContainer != null) {
				setListShown(false, false);
			}
		}
		mHandler.post(mRequestFocus);
	}

	/**
	 * Control whether the list is being displayed. You can make it not
	 * displayed if you are waiting for the initial data to show in it. During
	 * this time an indeterminant progress indicator will be shown instead.
	 * 
	 * @param shown If true, the list view is shown; if false, the progress
	 *            indicator. The initial value is true.
	 * @param animate If true, an animation will be used to transition to the
	 *            new state.
	 */
	private void setListShown(final boolean shown, final boolean animate) {
		ensureList();
		if (mProgressContainer == null) throw new IllegalStateException("Can't be used with a custom content view");
		if (mListShown == shown) return;
		mListShown = shown;
		if (shown) {
			if (animate) {
				mProgressContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_out));
				mListContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_in));
			} else {
				mProgressContainer.clearAnimation();
				mListContainer.clearAnimation();
			}
			mProgressContainer.setVisibility(View.GONE);
			mListContainer.setVisibility(View.VISIBLE);
		} else {
			if (animate) {
				mProgressContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_in));
				mListContainer.startAnimation(AnimationUtils.loadAnimation(getActivity(), android.R.anim.fade_out));
			} else {
				mProgressContainer.clearAnimation();
				mListContainer.clearAnimation();
			}
			mProgressContainer.setVisibility(View.VISIBLE);
			mListContainer.setVisibility(View.GONE);
		}
	}
}